In an exponential function f(x) = bx, the base b is a positive number not equal to

Question:

In an exponential function f(x) = bx, the base b is a positive number not equal to 1. In this exercise, you will explore what happens if we try to define a function whose base is negative. Consider f(x) = (-4)x.
a. Explain why f (1/2) is undefined.
b. Explain why f (1/4) is undefined.